In May, Samsung, as expected, introduced the 50-megapixel image sensor for the cameras of the ISOCELL GN1 smartphones. As the manufacturer said then, a 50-megapixel sensor will allow for brighter images and faster autofocus, and is the first to implement both Tetracell and Dual Pixel technologies. Now Samsung has published a video and details about this curious sensor.
As is customary today, GN1 uses Quad Bayer technology (Tetracell in Samsung terminology): unlike conventional RGB sensors, in which pixels with different color filters are arranged in a mosaic pattern, in Samsung Tetracell pixels with the same color filter are arranged next to each other in groups of four. In bright light, the sensor receives an image close to 50 megapixels, and when there is a lack of light, neighboring pixels are combined into a 2 × 2 array to produce 2.4 μm diodes with a resulting 12.5-megapixel image.
One of the key indicators of cameras is the speed of focusing on the subject. Fast autofocus will help you not to miss a precious moment – for this, the ISOCELL GN1 sensor uses Dual Pixel technology with 100 million phase detection focus units. Each pixel in ISOCELL GN1 consists of two photodiodes receiving light rays from a microlens placed on top of the pixel. Then, in the process of autofocus with deduction of the phase difference, two “copies” of the image from the incident light are created, one on each photodiode, which are evaluated by the sensor. After that, the lens is adjusted until the two images become identical – that means the object is in perfect focus. The technology also improves quality using Real-time HDR technology: instead of combining several photos, each pixel in a cluster of four takes a picture with a different exposure time: two pixels shoot with an average exposure time, one with a long exposure and the other with a short one. The result is a photo in an extended color range in one frame.
This autofocus is much faster than traditional contrast analysis systems. Moreover, the process speed depends on the number of pixels with phase detectors installed in the sensor. In many smartphones, the number of pixels with phase detection support is only 5–10%, but ISOCELL GN1 uses two photodiodes per pixel.
The size of the sensor is an impressive 1 / 1.31 “at a resolution of 50 megapixels (8160 × 6144 pixels). For comparison: the 108-megapixel sensor ISOCELL Bright HM1 from the same Samsung installed in the Galaxy S20 Ultra has almost the same physical dimensions 1/1 , 33 “(due to twice as small pixels – 0.8 microns). The company noted that thanks to the Dual Pixel and the use of software algorithms, photos taken using ISOCELL GN1 are comparable in quality to images with a resolution of up to 100 megapixels.
The sensor, of course, uses Samsung’s innovative pixel isolation technology Samsung ISOCELL Plus, which uses a physical barrier that allows the microlens to direct more light to the photodiodes. As a result, color accuracy is improved and photosensitivity is improved, which means bright and rich colors are provided.
Finally, unlike traditional image sensors, GN1 has not one but two “native” ISO values: low and high. Thanks to this, it ensures accurate operation in bright conditions, and Smart-ISO technology selects the ideal conversion factor for various conditions. This allows you to choose the most optimal dynamic range and reduce noise.
So, when shooting portraits on the beach on a sunny day, the technology selects a low value of its own ISO sensitivity to increase the full capacity of the potential well and expand the dynamic range of the image for bright portions of the scene. And when taking a selfie with friends at a party late in the evening, Smart-ISO technology will select a higher native ISO for optimal brightness with less noise.
If you notice an error, select it with the mouse and press CTRL + ENTER.